"Investors aren't convinced that technology spending will rise uniformly year over year," says Kim Caughey Forrest, portfolio manager at Fort Pitt Capital and one of the few to predict the crash in Apple (AAPL) stock. "They're probably right."

The lagging nature of tech stocks has been eye-opening for investors who assume that if there's a bull market, tech is probably the leader. Techs have been disappointing in a number of regards, including:

• The cratering of tech darling Apple. Apple, the fad stock of 2012, is quickly souring. The latest bad news came from Cirrus Logic, supplier of audio chips to Apple, which said inventory is piling up amid weak demand. That comes just a week after tech tracker IDC reported Mac sales fell 8% in the first quarter. "With tech and consumer devices, what's in is in and what is out is out," says Caughey Forrest, adding smartphones and tablets are maturing in developed countries and Apple products aren't as popular as bulls thought they would be in emerging nations. Shares of Apple have since collapsed 40% from their high, falling $23.44, or $5.5%, Wednesday to close at $402.80. With a market value of $378 billion, Apple has lost its perch as the most valuable company to ExxonMobil at $385.3 billion.

• Overall tech sector hit. Apple's crash is the clearest sign of tech's troubles, but it's not alone. Technology stocks are up 1.3% over the past three months, making the sector the third-worst of the 10 tracked by S&P Capital IQ. Big bellwether stocks such as Google (GOOG), Oracle (ORCL), Netflix (NFLX) and Qualcomm (QCOM) are all down since the end of February. Meanwhile, investors are focusing on defensive sectors that tend to hold up better during downturns, such as telecom (up 14.5%), health care (up 14.5%) and consumer staples (up 12.8%).

• Earnings growth questions from tech. Rather than delivering solid earnings growth, tech is one of the drags. During the first quarter, analysts are expecting companies to report 2.0% lower earnings growth, says S&P Capital IQ, while overall Standard & Poor's 500 earnings are expected to rise 1.2%.

There are other factors complicating things, too. If investors are expecting the economy to slow, they're taking it out first on economically sensitive stocks like tech, says Jack Ablin of BMO Private Bank.

Investors start getting antsy to sell stocks in May, and tech stocks are especially susceptible to spring selling, says Robert Maltbie of Millennium Asset Management. "You don't want to own tech going into a summer slowdown," he says.